1. Field of the Invention
The present invention relates to an integrated optical module, and more particularly, to an optical module in which a light source and a photodetector are connected with each other by a flexible printed circuit board.
2. Description of the Related Art
Miniaturized portable digital terminals that possess complicated functionalities and various configurations are well-known and have been disclosed in the art. These digital terminals include products such as mobile telephones, digital cameras, digital camcorders, game consoles, PMP (portable media player), etc. These digital terminals typically are of a miniature size, so as to be conveniently carried, while being capable of processing large amounts of data. In consideration of these facts, the miniaturized digital terminals currently on the market are configured to be connected by a serial interface using an FPCB (flexible printed circuit board) as a transmission medium.
Specifically, the serial interface using the FPCB is required to have high operational reliability with a minimized power consumption level. In the case of using a conventional FPCB as a signal transmission medium, while maintaining a desired data processing amount, limitations exist in increasing data transmission speed as such increases in speed cause comparable increases in the generation electromagnetic interference (EMI). Matsushita Electric, for example, has disclosed an optical connection structure in which a polymide optical waveguide is formed in a conventional FPCB and an optical device is flip-chip bonded to the polymide optical waveguide through patterning as a method for overcoming the aforementioned generation of EMI.
The optical connection structure disclosed by Matsushita includes a light source for transmitting data, a photodetector for receiving data, and an optical waveguide coupled to a FPCB that is used as a transmission media for transmitting and receiving data. The light source and the photodetector correspond to each other in a one-to-one relationship and a plurality of light sources and photodetectors may be used as the situation demands.
However, the optical connection structure disclosed by Matsushita has a drawback in that it is difficult to achieve a high degree of operational reliability between the optical devices when a plurality of optical devices are integrated on the FPCB. Also, in the region where the existing FPCB and the optical device are connected with each other, the volume of the entire configuration increases.